Ultrasonic robotic tool actuation

ABSTRACT

Described herein include various embodiments of a tool assembly for performing endoscopic surgery that can be used manually and/or with a robotic surgical system. The tool assembly can include a shaft assembly that extends from a housing of the tool assembly. A distal end of the shaft can include an end effector that includes a clamp arm pivotally coupled to a blade for cutting and/or sealing tissue. Pivoting of the clamp arm between the open and closed configurations can be caused by movement of a yoke that is slidably disposed within the housing of the tool assembly. For example, the yoke can be caused to move by one or more outputs (e.g., a manual output, a rotary output, and/or a linear mechanical output). Furthermore, some tool assembly embodiments can include a biasing system that biases the yoke such that the clamp arm is in the open configuration. In some embodiments, the tool assembly can be configured for tissue spread dissection using the clamp arm and blade.

FIELD OF THE INVENTION

The present disclosure relates generally to methods, systems, anddevices for controlling the pivoting of a clamp arm of an end effectorof a surgical tool.

BACKGROUND OF THE INVENTION

Minimally invasive surgical (MIS) instruments are often preferred overtraditional open surgical devices due to the reduced post-operativerecovery time and minimal scarring. Laparoscopic surgery is one type ofMIS procedure in which one or more small incisions are formed in theabdomen and a trocar is inserted through the incision to form a pathwaythat provides access to the abdominal cavity. The trocar is used tointroduce various instruments and tools into the abdominal cavity, aswell as to provide insufflation to elevate the abdominal wall above theorgans. The instruments and tools can be used to engage and/or treattissue in a number of ways to achieve a diagnostic or therapeuticeffect. Endoscopic surgery is another type of MIS procedure in whichelongate flexible shafts are introduced into the body through a naturalorifice.

Endoscopic surgical instruments are often preferred over traditionalopen surgical devices since a smaller incision tends to reduce thepost-operative recovery time and complications. Consequently,significant development has gone into a range of endoscopic surgicalinstruments that are suitable for precise placement of a distal endeffector at a desired surgical site through a cannula of a trocar. Thesedistal end effectors engage the tissue in a number of ways to achieve adiagnostic or therapeutic effect (e.g., endocutter, grasper, cutter,staplers, clip applier, access device, drug/gene therapy deliverydevice, and energy device using ultrasound, RF, laser, etc.).

Some endoscopic surgeries require a surgical tool having an end effectorpositioned at a distal end of an elongate shaft that can performfunctions, such as assist with grasping tissue, cutting tissue, sealingtissue, and/or releasing tissue. Such functions can require at least oneinput from a mechanical driving source (e.g., tool driver) to activatemechanisms within the surgical tool. These mechanisms and inputs can addunwanted complexity, size, weight, and cost to endoscopic surgery tools.

SUMMARY OF THE INVENTION

Methods, systems, and devices are provided for pivoting a clamp arm ofan end effector of a surgical tool. In one embodiment, a surgical toolis provided and can include a housing and a shaft assembly that extendsthrough the housing and distally from the housing. The shaft assemblycan include a distal end with a blade and a clamp arm pivotally coupledrelative to the blade. The surgical tool can also include a yokedisposed within the housing and slidably disposed around the shaftassembly. The yoke can be operatively coupled between a first actuatorprojecting from the housing and the clamp arm such that movement of thefirst actuator causes longitudinal translation of the yoke along theshaft assembly to thereby move the clamp arm between the open and closedpositions. The surgical tool can also include an ultrasonic transducerdisposed within the housing and coupled to the blade for deliveringultrasonic energy to the blade.

In one embodiment, the surgical tool can include at least one springdisposed within the housing and biasing the yoke distally to bias theclamp arm to the open position. The spring can be configured to compresswhen the yoke is moved proximally within the housing to move the clamparm to the closed position. In certain aspects, the surgical tool caninclude first and second springs disposed within the housing. The secondspring can be configured to compress subsequent to compression of thefirst spring as a result of movement of the yoke in the proximaldirection. The clamp arm can be configured to apply a first forceagainst tissue engaged between the clamp arm and the blade during afirst range of motion of the yoke, and the clamp arm can be configuredto apply a second force against tissue engaged between the clamp arm andthe blade during a second range of motion of the yoke.

In another embodiment, the first actuator can be configured to linearlytranslate to cause longitudinal translation of the yoke in a firstdirection. The surgical tool can include a second actuator configured tolinearly translate to cause longitudinal translation of the yoke in asecond direction, the second direction being in a direction oppositefrom the first direction.

In other embodiments, the first actuator can be configured to rotate tocause longitudinal translation of the yoke. Rotation of the firstactuator can cause a lead screw disposed within the housing to rotate,and rotation of the lead screw can cause longitudinal translation of theyoke. In certain embodiments, the yoke can be operatively coupled to thefirst actuator by a pulley assembly, a lever, or a pinion gear. Thefirst actuator can be configured to move a first distance therebycausing the yoke to move a second distance, and the first distance canbe greater than the second distance. In certain exemplary embodiments,the first actuator can include at least one protrusion formed on theyoke and extending through an opening in the housing. The housing can beconfigured to couple to a driver of a robotic arm of a robotic surgicalsystem.

Surgical methods are also provided, and in one embodiment the methodincludes actuating a motor on a driver tool of a surgical robot to causethe motor to apply a force to an actuator on a surgical tool. Movementof the actuator can cause a yoke disposed within a housing of thesurgical tool to translate linearly about a shaft assembly extendingthrough the housing. Translation of the yoke can cause a clamp arm on anend effector of the surgical tool to move from an open position to aclosed position to thereby engage tissue between the clamp arm and ablade.

In certain embodiments, proximal translation of the yoke can compress abiasing member that biases the yoke distally. In other aspects, themotor can apply one of a linear force and a rotational force to theactuator to cause the yoke to translate linearly. Movement of the yoke afirst distance can cause the clamp arm to apply a first force againstthe tissue engaged between the clamp arm and the blade, and furthermovement of the yoke a second distance can cause the clamp arm to applya second force against the tissue engaged between the clamp arm and theblade with the second force being greater than the first force.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective view of one embodiment of a surgical roboticsystem that eludes a patient-side portion and a user-side portion;

FIG. 2 is a side perspective view of a robotic arm of the surgicalrobotic system of FIG. 1 with a tool assembly slidably engaged with atool driver of the robotic arm;

FIG. 3 is a perspective view of the tool driver of the robotic arm ofFIG. 2;

FIG. 4A is a side perspective view of one exemplary embodiment of a toolassembly having an elongate shaft extending from a housing and an endeffector at a distal end of the elongate shaft;

FIG. 4B is a side perspective view of a distal portion of the toolassembly of FIG. 4A, showing the end effector including a clamping armrelatively pivotally coupled to a blade;

FIG. 4C is a side perspective view of a proximal portion of the housingof FIG. 4A, with at least one linear input coupling;

FIG. 4D is a side perspective cross-sectional view of the housing ofFIG. 4A, with a yoke slidably disposed within the housing of the toolassembly;

FIG. 4E is a side perspective view of a proximal portion of the housingof FIG. 4A, with a sterile barrier covering a portion of the housing;

FIG. 5 is a partial cross-sectional view of another embodiment of a tooldriver having a yoke coupled to two linear input couplings and a biasingsystem including a pair of springs;

FIG. 6 is a partial cross-sectional view of yet another embodiment of atool driver having a yoke coupled to a single linear input coupling anda biasing system including a single spring;

FIG. 7A is a side perspective view of another embodiment of a yokecontrolled by two linear actuators;

FIG. 7B is a side perspective view of yet another embodiment of a yokecontrolled by two linear actuators;

FIG. 8 is a side perspective view of another embodiment of a yoke andbiasing system including a compound gear;

FIG. 9 is a side perspective view of another embodiment of a yoke andbiasing system including a lever arm; and

FIG. 10 is a partial cross-sectional view of yet another embodiment of atool driver having a yoke and biasing member controlled by a rotaryoutput.

DETAILED DESCRIPTION OF THE INVENTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

Further, in the present disclosure, like-named components of theembodiments generally have similar features, and thus within aparticular embodiment each feature of each like-named component is notnecessarily fully elaborated upon. Additionally, to the extent thatlinear or circular dimensions are used in the description of thedisclosed systems, devices, and methods, such dimensions are notintended to limit the types of shapes that can be used in conjunctionwith such systems, devices, and methods. A person skilled in the artwill recognize that an equivalent to such linear and circular dimensionscan easily be determined for any geometric shape. Sizes and shapes ofthe systems and devices, and the components thereof, can depend at leaston the anatomy of the subject in which the systems and devices will beused, the size and shape of components with which the systems anddevices will be used, and the methods and procedures in which thesystems and devices will be used.

In general, various embodiments of a tool assembly are provided forperforming endoscopic surgery that can be used manually and/or with arobotic surgical system. The tool assembly can include a shaft assemblythat extends within and distally from a housing of the tool assembly. Adistal end of the shaft can include an end effector having a clamp armpivotally coupled to a blade. For example, such an arrangement of theend effector can be used for cutting and/or sealing tissue during asurgical procedure. In order to cut or seal tissue, the clamp arm can bein an open configuration to allow tissue to be positioned between theclamp arm and the blade. The clamp arm can be caused to pivot to aclosed configuration thereby compressing tissue between the clamp armand blade to assist the blade with cutting and/or sealing the tissue,including ultrasonically. Such pivoting by the clamp arm between theopen and closed configurations can be caused by movement of a yoke thatis slidably disposed within the housing of the tool assembly. In sometool assembly embodiments described herein, the yoke is caused to moveby one or more actuators or inputs (e.g., manual input, rotary and/orlinear mechanical input) thereby causing the clamp arm to pivot toeither an open configuration or a closed configuration. Furthermore,some tool assembly embodiments described herein include a biasing systemwithin the housing that biases the yoke such that the clamp arm isbiased to an open configuration, thereby only requiring a mechanical ormanual output to apply a force to pivot the clamp arm into the closedconfiguration. In some embodiments, the tool assembly can be configuredfor tissue spread dissection, such as by using the clamp arm and bladeto apply a great enough force against surrounding tissue to spreadtissue during a surgical procedure.

As indicated above, in one embodiment the systems, devices, and methodsdisclosed herein can be implemented using a robotic surgical system. Aswill be appreciated by a person skilled in the art, electroniccommunication between various components of a robotic surgical systemcan be wired or wireless. A person skilled in the art will alsoappreciate that all electronic communication in the system can be wired,all electronic communication in the system can be wireless, or someportions of the system can be in wired communication and other portionsof the system can be in wireless communication.

FIG. 1 is a perspective view of one embodiment of a surgical roboticsystem 100 that includes a patient-side portion 105 that is positionedadjacent to a patient P, and a user-side portion 107 that is located adistance from the patient, either in the same room and/or in a remotelocation. The patient-side portion 105 generally includes one or morerobotic arms 110 and one or more tool assemblies 120 that are configuredto releasably couple to a robotic arm 110. The user-side portion 107generally includes a vision system 152 for viewing the patient and/orsurgical site, and a control system 154 for controlling the movement ofthe robotic arms 110 and each tool assembly 120 during a surgicalprocedure.

The control system 54 can have a variety of configurations and it can belocated adjacent to the patient, e.g., in the operating room, remotefrom the patient, e.g., in a separate control room, or it can bedistributed at two or more locations. For example, a dedicated systemcontrol console can be located in the operating room, and a separateconsole can be located in a remote location. The control system 154 caninclude components that enable a user to view a surgical site of apatient being operated on by the patient-side portion 105 and/or tocontrol one or more parts of the patient-side portion 105 (e.g., toperform a surgical procedure at the surgical site). In some embodiments,the control system 154 can also include one or more manually-operateduser input devices, such as a joystick, exoskeletal glove, a powered andgravity-compensated manipulator, or the like. These user input devicescan control tele-operated motors which, in turn, control the movement ofthe surgical system, including the robotic arms 110 and tool assemblies120.

The patient-side portion 105 can also have a variety of configurations.As depicted in FIG. 1, the patient-side portion 105 can couple to anoperating table T. However, in some embodiments, the patient-sideportion 105 can be mounted to a wall, to the ceiling, to the floor, orto other operating room equipment. Further, while the patient-sideportion 105 is shown as including two robotic arms 110, more or fewerrobotic arms 110 may be included. Furthermore, the patient-side portion105 can include separate robotic arms 110 mounted in various positions,such as relative to the surgical table T (as shown in FIG. 1).Alternatively, the patient-side portion 105 can include a singleassembly that includes one or more robotic arms 110 extending therefrom.

FIG. 2 illustrates the robotic arm 110 and tool assembly 120 releasablycoupled to the robotic arm 110 in more detail. The robotic arm 110 cansupport and move the associated tool assembly 120 along one or moremechanical degrees of freedom g all six Cartesian degrees of freedom,five or fewer Cartesian degrees of freedom, etc.).

The robotic arm 110 can include a tool driver 112 at a distal end of therobotic arm 110, which can assist with controlling features associatedwith the tool assembly 120. While not shown, the tool driver 112 caninclude one or more motors with shafts that either rotate or translate,and that couple to the tool assembly to effect motion of variouscomponents of the tool assembly. The robotic arm 110 can also include anentry guide (e.g., a cannula mount or cannula) that can be a part of orremovably coupled to the robotic arm 110, as shown in FIG. 2. A shaft ofthe tool assembly 120 can be inserted through the driver 112 and thecannula for insertion into a patient. A person skilled in the art willappreciate that the configuration of the robotic arm can vary, and thatthe tool assemblies disclosed herein can be used with any robotic arm.

FIG. 3 illustrates the tool driver 112 in more detail. As shown, thetool driver 112 can include one or more motors, e.g., four motors 114a-114 d are shown, that control a variety of movements and actionsassociated with the tool assembly 120, as will be described in greaterdetail below. For example, any of the motors 114 a-114 d can beassociated with a mechanical rotary output or a mechanical linearoutput, either of which can be configured to couple to a rotary inputcoupling or a linear input coupling associated with the tool assemblyfor actuating at least one mechanism of the tool assembly. The tooldriver 112 can also include a shaft-receiving channel 116 formed in asidewall thereof for receiving the shaft of the tool assembly 120. Inother embodiments, the shaft can extend through on opening in the tooldriver 112, or the two components can mate in various otherconfigurations.

FIGS. 4A-4E illustrate an exemplary embodiment of a tool assembly 220having a housing 222 coupled to a proximal end of a shaft 224 and an endeffector 226 coupled to a distal end of the shaft 224. The end effector226 can include a clamp arm 228 that pivots relative to a blade 229. Theclamp arm 228 can pivot between an open configuration where the clamparm 228 and blade 229 are configured to receive tissue therebetween(see, for example, FIG. 4B) and a closed configuration where the clamparm 228 and blade 229 are configured to either cut or seal tissuetherebetween. The blade 229 can be ultrasonic and in communication witha transducer 223 that provides ultrasonic energy to the blade 229. Forexample, the housing 222 can include the transducer 223 (as shown inFIG. 4D) with a piezoelectric element that together generate amechanical motion (e.g., vibration) at the blade 229. Movement of theclamp arm 228 to the closed configuration to compress tissue between theclamp arm 228 and blade 229 can improve the ability of the blade 223 totransfer ultrasonic energy to tissue for sealing and/or cutting tissue.

The housing 222 can include coupling features that assist withreleasably coupling the housing 222 to the tool driver 112 of therobotic arm 110. For example, the housing 222 can include mechanismsthat can be actuated by the one or more motors 114 a-114 d in the driver112. As discussed above, any of the motors 114 a-114 d can be associatedwith a rotary or linear mechanical output (e.g., a rotating shaft or alinearly translating shaft), either of which can be configured to coupleto a rotary input coupling or a linear input coupling on the toolassembly 120 for actuating at least one mechanism of the tool assembly120. For example, as shown in FIG. 4C, an actuator, referred to as alinear input coupling 230, can project outward from the housing 222 andit can interact with a linear mechanical output of the tool driver 112such that when the linear mechanical output is activated by one of themotors 114 a-114 d, the linear mechanical output can push on andtranslate the linear input coupling 230 thereby actuating a mechanismwithin the housing 222 for controlling one or more functions of the toolassembly 220. Such mechanism, for example, can control the operation ofvarious features associated with the end effector 226 (e.g., pivoting ofclamp arm 228 relative to blade 229, etc.), as will be described ingreater detail below. In an exemplary embodiment, when the tool housing222 is coupled to the tool driver 112, the tool driver 112 is positioneddistal of the tool housing 222 such that the tool driver's mechanicaloutputs (e.g., linear and/or rotary mechanical outputs) are located at aproximal end of the tool driver 112. The mechanical outputs can interactwith one or more inputs (e.g., the linear input coupling 230) located atthe distal end of the tool housing 222. As a result of thisconfiguration, proximal translation of a linear output on the tooldriver 112 can act on and cause the tool's linear input coupling totravel proximally to active a mechanism within the tool housing 222.Furthermore, although the tool assembly 120 is described as having onelinear input coupling 230, any of the tool assemblies described herein(including tool assembly 120) can include more than one rotary or linearinput couplings that can be acted on by at least one output (e.g.,manual, rotary and/or linear mechanical output) on a tool driver of asurgical robot for activating one or more mechanisms associated with thetool assembly. An exemplary embodiment of a tool driving having lineardrivers is described in more detail in U.S. patent application Ser. No.15/381,453 filed Dec. 16, 2016 and entitled “Methods and Systems forCoupling a Surgical Tool to a Tool Driver of a Robotic Surgical System,”and U.S. patent application Ser. No. 15/381,508 filed Dec. 16, 2016 andentitled “Methods and Systems for Coupling a Surgical Tool to a ToolDriver of a Robotic Surgical System.”

The shaft 224 can include drive assemblies extending along or throughthe shaft 224 for controlling the actuation and/or movement of the endeffector 226 (e.g., pivoting of clamp arm 228 relative to blade 229).The end effector 226 can include any of a variety of surgical tools,such as the clamp arm 228 and blade 229, a stapler, a clip applier,forceps, a needle driver, a cautery device, a cutting tool, a pair ofjaws, an imaging device (e.g., an endoscope or ultrasound probe), or acombined device that includes a combination of various tools. In theillustrated embodiment, the shaft 224 includes an inner closure tube 235that extends therealong and that is slidably disposed relative to anouter closure tube 236 that is in fixed relation to the tool housing222. A distal end of the inner closure tube 235 can be pivotally coupledto the clamp arm 228 such that proximal travel of the inner closure tube235 causes the clamp arm 228 to pivot to the closed configuration anddistal travel of the inner closure tube 235 causes the clamp arm 228 topivot to the open configuration. Although the outer closure tube 236 isdescribed as being in fixed relation relative to the tool housing 222and the inner closure tube 235 is described as being slidably disposedrelative to the outer closure tube 236, the inner closure tube 235 canbe in fixed relation relative to the tool housing 222 and the outerclosure tube 236 can be slidably disposed relative to the inner closuretube 235 without departing from the scope of this disclosure.

In one exemplary embodiment, as shown in FIG. 4D, the tool assembly 220can include a yoke 233 that has an elongated tubular body that isslidably disposed within the housing. The yoke 233 can be coupled to orintegral with the linear input coupling 230, and the yoke 233 can alsocouple to the inner closure tube 235. As a result when the linear inputcoupling 230 is actuated and caused to move (e.g., via manually or by alinear mechanical output), the yoke 233 and inner closure tube 235 arecaused to move thereby pivoting the clamp arm 228 between open andclosed configurations. For example, when the linear input coupling 230is actuated causing it to translate in a proximal direction, the yoke233 and inner closure tube 235 can also be caused to translate in theproximal direction thereby pivoting the clamp arm 228 to the closedconfiguration. Deactivation or distal retraction of the linear outputcan allow or cause the yoke 233 and inner closure tube 235 to translatein a distal direction thereby pivoting the clamp arm 228 to the openconfiguration.

As shown in FIG. 4D, the tool assembly 220 includes a biasing system 234that biases the yoke 233 in the distal direction and that biases theclamp arm 228 to the open configuration. For example, the biasing system234 can bias the yoke 233 in a distal position, when there is noactivation force (e.g., either manually or via a mechanical output)acting on the linear input coupling 230. As shown in FIG. 4D, thebiasing system 234 can include a distal biasing member 248, such as afirst spring, positioned between a distal compressing member 250 and amiddle compressing member 252. The distal and middle compressing members250, 252 can be, for example, washers and they can be slidably disposedalong their respective inner openings along a proximal end of the outerclosure tube 235, as shown in FIG. 4D. The yoke 233 can be rigidlycoupled to the distal compressing member 250 such that proximal movementof the yoke 233 causes corresponding movement of the distal compressingmember 250 in the proximal direction. The biasing system 234 can furtherinclude a proximal biasing member 249, such as a second spring,positioned between the middle compressing member 252 and a proximalcompressing member 254. The distal, middle, and proximal compressingmembers 250, 252, 254 can be axially aligned (e.g., along a centralaxis) with each other, and can also be axially aligned with the distaland proximal biasing members 248, 249.

As noted above, the yoke 233 can be directly coupled to the distalcompressing member 250 such that when the yoke 233 moves in the proximaldirection (e.g., thereby pivoting the clamp arm 228 to the closedconfiguration), the distal compressing member 250 is moved in theproximal direction thereby compressing the distal biasing member 248between the distal compressing member 250 and the middle compressingmember 252. After the yoke 233 and distal compressing member 250 havemoved a first distance thereby compressing the distal biasing member248, the yoke 233 can continue to move in the proximal direction alongwith the distal compressing member 250, the distal biasing member 248,and the middle compressing member 252. As a result, the proximal biasingmember 249 is compressed between the middle compressing member 252 andthe proximal compressing member 254. In an exemplary embodiment, thedistal biasing member 248 can have a first spring force that, whencompressed, allows the clamp arm 228 to pivot into a closed orsubstantially closed configuration, and the proximal biasing member 249can have a second spring force that, when compressed, allows the clamparm 228 to apply compressive forces against tissue positioned betweenthe clamp arm 228 and the blade 229. For example, the second springforce can be greater than the first spring force thereby allowing theclamp arm 228 to apply a greater force against tissue as the proximalbiasing member is compressed compared to when the distal biasing memberis compressed. The greater second spring force provided by the proximalbiasing member can assist with allowing the blade 229 to seal and/or cuttissue positioned between the blade 229 and clamp arm 228. When manualor mechanical linear outputs are no longer applied to the linear inputcoupling 230, the distal and proximal biasing members 248, 249 canexpand, thereby distally translating the middle and distal compressingmembers 252, 250, as well as the yoke 233 coupled to the distalcompressing member 250, and pivoting the clamp arm 228 to the openconfiguration.

FIG. 4E illustrates a sterile barrier 240 that can cover at least aportion of the outer surface of the housing 222 of the tool assembly220. The sterile barrier 240 can be configured to provide a sterilebarrier for the housing 222 while not interfering with couplingmechanisms that allow the tool assembly 220 to couple to the robotic arm110, as well as not interferimg with manual and/or mechanical inputs foractuating mechanisms associated with the tool assembly 220. For example,the sterile barrier 240 can allow the linear input coupling 230 to beacted upon by a linear mechanical output of the tool driver 112, as wellas allow the linear input coupling 230 to translate thereby translatingthe yoke 233 to pivot the clamp arm 228. While not shown, a bag or drapecan extend from the sterile barrier 240 to cover the robotic arm. Asterile component, such as an instrument sterile adapter (ISA) (notshown), can also be placed at the connecting interface between the toolassembly 120 and the robotic arm 110. The placement of an ISA betweenthe tool assembly 120 and the robotic arm 110 can ensure a sterilecoupling point for the tool assembly 120 and the robotic arm 110. Thispermits removal of tool assemblies 120 from the robotic arm 110 toexchange with other tool assemblies 120 during the course of a surgerywithout compromising the sterile surgical field.

Some embodiments of the tool assemblies disclosed herein can beconfigured to assist with tissue spread dissection using the clamp arm228 and blade 229. As referred to herein, tissue spread dissection usingthe clamp arm 228 and blade 229 can include positioning the clamp arm228 and blade 229 in a space between opposing tissue and pivoting theclamp arm 228 away from the blade 229 (from the closing configurationinto an open configuration) thereby increasing the space between theopposing tissue. For example, such tissue spread dissection can beuseful for passing objects through tissue, mobilization and/or viewinganatomy.

As discussed above, a biasing system 234 can cause the yoke 233 totranslate in a distal direction once linear outputs are no longer actingon the linear input coupling 230, thus allowing the jaws to return tothe open configuration. As such, the biasing system 234 can beconfigured such that it translates a force (e.g., tissue spreaddissection force) through the yoke 233 and to the clamp arm 228 that issufficient for allowing the clamp arm 228 to pivot to the openconfiguration thereby creating spread dissection to surrounding tissue.Due to the increased force requirements to spread tissue (compared tojust pivoting the clamp arm 228 to an open configuration), the yoke 233and/or associated mechanisms that assist with controlling the movementof the yoke (e.g., biasing system 234) can be configured to provideadditional force to the clamp arm 228 for spreading tissue. Suchadditional force can be provided using currently available mechanicaloutputs, which may be less than the force requirements needed for tissuespread dissection. As such, some of the embodiments disclosed herein caninclude a mechanical advantage that, for example, increases the amountof force provided between the mechanical output and the clamp arm 228,as will be described in greater detail below.

For example, a spreading force applied to the opposing tissue forperforming sue spread dissection can require approximately 25 pounds offorce to approximately 35 pounds of force. As such, biasing systemsand/or or mechanical output mechanisms described herein that areoperatively coupled to the clamp arm 228 can be configured to providesuch required force for spread dissection. Furthermore, the biasingsystems and/or or mechanical input mechanisms can be configured forproviding more or less force without departing from the scope of thisdisclosure.

FIG. 5 illustrates an embodiment of a tool assembly 320 including a yoke333 coupled to a biasing system 334 that is configured to assist withtissue spread dissection, as will be described in greater detail below.As shown in FIG. 5, the yoke 333 can be positioned within and slidablydisposed relative to the housing 322 of the tool assembly 320. The yoke333 can be coupled to an inner closure tube 335 that extends along anouter tube 336 and shaft, with the inner tube 335 being operativelycoupled to a clamp arm that can pivot relative to a blade (such as theclamp arm 228 and blade 229 of tool assembly 220). Similar to theembodiment described above with reference to tool assembly 220, when theyoke 333 is caused to translate, the inner closure tube 335 is caused totranslate thereby causing the clamp arm to pivot between an open andclosed configuration relative to the blade.

As shown in FIG. 5, the yoke 333 can include an extension 360 thatcouples to and extends between the inner closure tube 335 and a pair ofyoke arms 362 that extend approximately parallel to a longitudinal axisof the inner closure tube 335. For example, the extension 360 can extendapproximately perpendicular relative to the longitudinal axis of theinner closure tube 335. A distal end of each of the yoke arms 362 caninclude linear coupling inputs 330 that are configured to couple tolinear mechanical outputs, such as from the tool driver 112. A proximalend of each of the yoke arms 362 can include a biasing coupling 363(e.g., a flat surface) that is configured to couple to a biasing member348 (e.g., spring). The biasing members 348 can compress when the linearinput couplings 330 are each acted upon by a linear mechanical outputthereby driving the yoke 333 in the proximal direction and pivoting theclamp arm to the closed position. When the linear mechanical outputs nolonger apply a force against the yoke 333 (e.g., the linear mechanicaloutputs are deactivated), the biasing members 348 can each apply abiasing or spring force against the proximal end of the yoke 333 thattogether cause the yoke 333 to translate to the distal position therebypivoting the clamp arm to the open configuration and spreading tissue.As such, the biasing system 334 can cause the clamp arm to pivot intothe open configuration, including spreading tissue while pivoting intothe open configuration, without a mechanical output, such as from thetool driver 112.

In some circumstances, manual control of the clamp arm can be desired,such as during loss of power and/or when the tool assembly 320 isdisconnected from a robotic arm 110 and the clamp arm needs to be movedinto the closed configuration in order to remove the end effector fromthe patient and trocar. The tool assembly 320 can thus include a manualcontroller (not shown) that can extend from the yoke 333 and through thehousing 322 such that a user can manipulate the manual controller tomove the yoke 333 between the distal and proximal positions therebymanually controlling the pivoting of the clamp arm between the open andclosed configurations, respectively.

FIG. 6 illustrates another embodiment of a tool assembly 420 including ayoke 433 coupled to a biasing member or spring 434 positioned at aproximal end of the yoke for biasing the yoke 433 in the distaldirection, thereby biasing the clamp arm to an open configuration. Asshown in FIG. 6, the yoke 433 can include an elongated body that extendsgenerally parallel to a housing 422 of the tool assembly 420. The yoke433 can be slidably disposed within the housing 422 and coupled to aninner closure tube 435 by a closure tube coupling 437 that extendsbetween the inner closure tube 435 and a distal end of the yoke 433. Theinner closure tube 435 can slidably translate within an outer closuretube 436 that is fixed relative to the housing 422. Similar to theembodiment described above with reference to tool assembly 220, when theyoke 433 is caused to translate, the inner closure tube 435 translatesrelative to the outer closure tube 436 thereby causing a clamp arm topivot between open and closed configurations relative to a blade.

As shown in FIG. 6, a proximal end of the yoke 433 can be slidablycoupled to a linear input coupling assembly 465 that, when acted upon bya linear mechanical output, causes the yoke 433 to translate in aproximal direction thereby causing the clamp arm to pivot to a closedconfiguration. The linear input coupling assembly 465 can include avertical sliding shaft 467 positioned parallel to the yoke 433 and thelongitudinal axis of the inner closure tube 435. The vertical slidingshaft 467 can be constrained relative to the housing 422 such that thevertical sliding shaft 467 can only translate in a direction parallel tothe longitudinal axis of the inner closure tube 435. As shown in FIG. 6,the vertical sliding shaft 467 can include a vertical slot 468 having alength that defines a maximum length of travel of the vertical slidingshaft 467. A first pin 469 can extend from the housing 422 into the slot468 thereby controlling the travel of the vertical sliding shaft 467 towithin the bounds of the vertical slot 468.

The linear input coupling assembly 465 can further include a horizontalsliding shaft 470 that extends perpendicular relative to thelongitudinal axis of the inner closure tube 435, and that extendsbetween the vertical sliding shaft 467 and the yoke 433, as shown inFIG. 6. The horizontal sliding shaft 470 can be constrained relative tothe housing 422 such that the horizontal sliding shaft 470 can onlyslide in a direction perpendicular to the longitudinal axis of the innerclosure tube 435. As shown in FIG. 6, the horizontal sliding shaft 470can include a horizontal slot 471 having a length defining a maximumlength of travel of the horizontal slot 471. A second pin 472 can extendfrom the housing 422 into the horizontal slot 471 thereby controllingthe travel of the horizontal sliding shaft 470 to within the bounds ofthe horizontal slot 471.

A proximal end of the vertical sliding shaft 467 can include a firstangled end 480 that slidably mates with a second angled end 482 of thehorizontal sliding shaft 470. Such coupling allows the first angled end480 to slide along the second angled end 482 and push the horizontalsliding shaft 470 towards the yoke 433 as the vertical sliding shaft 467travels in the proximal direction (such as when the linear mechanicaloutput is activated). This sliding coupling also allows the secondangled end 482 to slide along the first angled end 480 and push thevertical sliding shaft 467 in the distal direction as the horizontalsliding shaft 470 travels towards the vertical sliding shaft 467 (suchas when the linear mechanical output is deactivated).

Furthermore, a proximal end of the yoke 433 can include an angled slot484 and the horizontal sliding shaft 470 can include a yoke pin 486 atan end adjacent the yoke 433. The yoke pin 486 can extend into and beslidable along the angled slot 484 such that when the horizontal slidingshaft 470 travels perpendicular to the longitudinal axis of the innerclosure tube 435, the yoke 433 is caused to travel parallel to thelongitudinal axis of the inner closure tube 435. For example, when thehorizontal sliding shaft 470 travels towards the yoke 433, the yoke 433is caused to move in the proximal direction thereby compressing thebiasing member 434 and pivoting the clamp arm into the closedconfiguration. In this configuration, the angled coupling between thehorizontal sliding shaft 470 and the yoke 433 can desensitize theeffects of the mechanical linear output relative to the pivoting of theclamp arm. For example, the vertical sliding arm 467 can travel a firstdistance that results in the yoke 433 traveling half of the firstdistance thereby pivoting the clamp arm a smaller distance compared tothe yoke having a 1:1 travel ratio with the vertical sliding shaft 467and/or mechanical liner output. The angled couplings of the linear inputcoupling assembly 465 can also provide a mechanical advantage such thatthe mechanical output force can be less than the spring force of thebiasing member 434 yet the linear input coupling assembly 465 can actupon the yoke 433 to compress the biasing member 434. For example, thebiasing member 434 can have sufficient spring force to drive the yoke433 in the distal direction to pivot the clamp arm for performing tissuespread dissection.

In some implementations, the linear input coupling assembly 465 can beconfigured to allow more than one linear mechanical output to apply aforce against the linear input coupling assembly 465, such as thevertical sliding shaft 467, for activating the linear input couplingassembly 465 and translating the yoke 433. Any number of mechanicaloutputs can activate the linear input coupling assembly 465 for causingthe yoke to translate in the proximal direction thereby pivoting theclamp arm to the closed configuration.

In some embodiments, the tool assembly 420 can include a manualcontroller (not shown) that can extend from the yoke 433 and through thehousing 422 such that a user can manipulate the manual controller tomove the yoke 433 between the distal and proximal positions therebymanually controlling the pivoting of the clamp arm between the open andclosed configurations. For example, manual control of the clamp arm canbe desired, such as during loss of power and/or when the tool assemblyis disconnected from a robotic arm and the clamp arm needs to be movedinto the closed configuration in order to remove the end effector fromthe patient and trocar.

In some implementations of the tool assembly, the linear mechanicaloutput can control bi-directional movement of the yoke, such as proximaland distal translation of the yoke relative to the housing of the toolassembly to cause the clamp arm to pivot between closed and openconfigurations, respectively. In such configurations, for example, themechanical output (e.g., from a tool driver) can assist with tissuespread dissection.

FIG. 7A illustrates another embodiment of a tool assembly 520 thatincludes a yoke 533 that can have bi-directional movement (e.g.,proximal and distal directed translation) controlled by mechanicallinear outputs. As shown in FIG. 7A, the yoke 533 can include anelongated body that extends generally parallel to a housing 522 of thetool assembly 520. The yoke 533 can be positioned within and slidablydisposed relative to a housing 522. The yoke 533 can be coupled to aninner closure tube 535 such that when the yoke 533 is caused totranslate between a distal and proximal position, the inner closure tube535 is caused to translate thereby causing a clamp arm at a distal endof the inner closure tube 535 to pivot between open and closedconfigurations, respectively, relative to a blade. The inner closuretube 535 can extend along and be slidably disposed relative to an outerclosure tube 536 that is fixed relative to the housing 522.

As shown in FIG. 7A, the yoke 533 can be coupled to an actuationassembly 565 that includes an opening actuator 567 and a closingactuator 569 that are each configured to couple to a linear mechanicaloutput for individually translating the opening and closing actuators567, 569 in a proximal direction. The actuation assembly 565 can furtherinclude a pulley system 570, which can include one or more pulleys thatconnect the closing actuator 569 to the opening actuator 567. Forexample, the closing actuator 569 can be directly coupled to the yoke533, as shown in FIG. 7A. The pulley system 570 can be configured suchthat when the closing actuator 569 is caused to move in the proximaldirection (thereby translating the yoke 533 in the proximal directionand pivoting the clamp arm to the closed configuration) the openingactuator 567 is caused to move distally. Furthermore, the pulley system570 can be configured such that when the opening actuator 567 is causedto move in the proximal direction, the closing actuator 569 is caused tomove in the distal direction thereby moving the yoke 533 distally andpivoting the clamp arm to the open configuration.

As shown in FIG. 7B, instead of the pulley system 570, a pinion gear 590can couple a closing actuator 569 b to an opening actuator 567 b. Forexample, the closing actuator 569 b can be directly coupled to the yoke533 b, as shown in FIG. 7B. The pinion gear 590 can be engaged with theclosing actuator 569 b along a first side of the pinion gear 590 andengaged with the opening actuator 567 b along a second side (e.g.,opposite the first side) of the pinion gear 590 such that when theclosing actuator is caused to move in the proximal direction (therebytranslating the yoke 533 b in the proximal direction and pivoting theclamp arm to the closed configuration) the opening actuator 567 b iscaused to move distally. Furthermore, when the opening actuator 567 b iscaused to move in the proximal direction, the pinion gear 590 can causethe closing actuator 569 b to move in the distal direction therebymoving the yoke 533 b distally and pivoting the clamp arm to the openconfiguration. Other mechanisms for coupling the opening actuator andclosing actuator, such as a pivoted linkage, have been contemplated andare within the scope of this disclosure.

FIG. 8 illustrates yet another embodiment of a tool assembly 620 thatincludes a yoke 633 that can also have bi-directional movement (e.g.,proximal and distal directed movement) controlled by mechanical linearoutputs. The yoke 633 can include an elongated body that extendsgenerally parallel to a housing of the tool assembly 620. The yoke 633can be positioned within and slidably disposed relative to a housing.The yoke 633 can be coupled to an inner closure tube 635 such that whenthe yoke 633 is caused to translate, the inner closure tube 635 iscaused to translate thereby pivoting a clamp arm open and closedconfigurations relative to a blade.

As shown in FIG. 8, the yoke 633 can be coupled to an actuation assembly665 that includes an opening actuator 667 and a closing actuator 669that are each configured to couple to a linear mechanical output forindividually translating the opening and closing actuators 667, 669 in aproximal direction. The actuation assembly 665 can further include acompound gear 660 that mechanically couples the closing actuator 669 tothe opening actuator 667. Furthermore, the compound gear 660 canmechanically couple the opening and closing actuators 667, 669 to theyoke 633 such that translational movement of either the opening orclosing actuators 667, 669 cause translation of the yoke 633.

For example, the compound gear 660 can include a first gear 661 and asecond gear 662 that share a pivot point or rotational axis 663 and areaffixed relative to each other such that they are forced to rotatetogether. Furthermore, the second gear 662 can have a smaller diameterthan the first gear 661, as shown in FIG. 8. For example, the diameterof the second gear 662 can be half of the diameter of the first gear661, thereby allowing the compound gear 660 to have a 2:1 mechanicaladvantage between the smaller second gear 662 and the larger first gear661. The larger first gear 661 can be coupled to the opening and closingactuators 667, 669 that are each positioned and engaged along opposingsides of the first gear 661, as shown in FIG. 8. The opening and closingactuators 667, 669 can be engaged with the first gear 661 such thatlinear translation of both the opening and closing actuators 667, 669 inopposite directions (e.g., opening actuator 667 translates in distaldirection and closing actuator 669 translates in proximal direction)causes the first gear 661 to rotate. The smaller second gear 662 can becoupled to the yoke 633 such that rotation of the second gear 662 causesthe yoke 633 to linearly translate. As such, linear movement of theopening and closing actuators 667, 669 can cause rotation of the firstand second gears 661, 662 thereby translating the yoke 633 and causingthe clamp arm 628 to pivot. Furthermore, as a first torque is applied tothe larger first gear 661, an output second torque (e.g., via the clamparm) from the smaller second gear 662 can be greater than the firsttorque, such as twice as much. Likewise, a first arc length resultingfrom rotation of the larger first gear 661 can be greater than a secondarc length resulting from the associated rotation of the smaller secondgear 662, such as twice as much. The compound gear can provide amechanical advantage such that more force is provided to the clamp armfor spread dissection than the amount of force applied to the first gearfrom the linear mechanical output. The compound gear can also providedesensitization between the mechanical linear actuator(s) and the yoke633 (and clamp arm) by having the yoke 633 translate at a slower ratethan the opening and closing actuators 667, 669 thereby allowing forimproved precision and control of the yoke 633 and clamp arm.

FIG. 9 illustrates yet another embodiment of a tool assembly 720 thatincludes a yoke 733 that can also have bi-directional movement (e.g.,proximal and distal directed movement) controlled by mechanical linearoutputs. The yoke 733 can include an elongated body that extendsgenerally parallel to a housing 722 of the tool assembly 720. The yoke733 can be positioned within and slidably disposed relative to thehousing 722. The yoke 733 can be coupled to an inner closure tube 735such that when the yoke 733 is caused to translate, the inner closuretube 735 is caused to translate thereby pivoting a clamp arm betweenopen and closed configurations relative to a blade.

As shown in FIG. 9, the yoke 733 can be coupled to a lever arm 770. Thelever arm 770 can be coupled to a pivot joint 750 at a first end. Insome embodiments, the pivot joint 750 can be affixed to the housing 722.The lever arm 770 can be coupled to or interface with an actuator orlinear input coupling 730 at a second end of the lever arm 770. At somepoint between the two ends of the lever arm 770, the lever arm 770 canbe pivotally coupled to the yoke 733 at a lever coupling 774, as shownin FIG. 9. This configuration can provide a mechanical advantage, suchas the mechanical output (via linear input coupling 730) to yoke 733having approximately a 2:1 travel ratio. For example, a travel distanceof the linear input coupling 730 (e.g., when acted upon by a linearmechanical output) can be twice as long as the resulting distance theyoke 733 travels. Furthermore, this configuration can provide a 1:2force mechanical advantage where the force applied by the mechanicallinear output can be half as much as the force applied to the yoke 733by the lever arm 770.

Although the embodiments described above discuss linear mechanicaloutputs for controlling the movement of the yoke for pivoting the clamparm, some implementations of the tool assembly can include a yoke thatis controlled by at least one mechanical rotary output, as will bedescribed in greater detail below.

FIG. 10 illustrates an embodiment of a tool assembly 820 having a yoke833 coupled to a actuation assembly 865 that is controlled by at leastone mechanical rotary output on a tool driver of a surgical robot. Asshown in FIG. 10, the yoke 833 can include an elongated body thatextends generally parallel to a housing 822 of the tool assembly 820.The yoke 833 can be slidably disposed within the housing 822 and coupledto an inner closure tube 835 by a closure tube coupling 837 that extendsbetween the inner closure tube 835 and a distal end of the yoke 833. Theinner closure tube 835 can slidably translate within an outer closuretube 836 that is fixed relative to the housing 822. When the yoke 833 iscaused to translate, the inner closure tube 835 translates relative tothe outer closure tube 836 thereby causing a clamp arm to pivot betweenopen and closed configurations relative to a blade.

As shown in FIG. 10, the actuation assembly 865 can include an axillaryshaft 890 that has a rotary input coupling 891 at a distal end that isconfigured to couple to a mechanical rotary output such that when themechanical rotary output is activated the auxiliary shaft 890 is causedto rotate. The actuation assembly 865 can further include a pulleyassembly 892 that can couple to and extend between the auxiliary shaft890 and a lead screw 893. As shown in FIG. 10, the lead screw 893 canextend from the yoke 833, such as from a proximal end, and can bethreadably coupled to the yoke 833 such that rotation of the lead screw893 causes the yoke 833 to translate. For example, when the lead screw893 rotates in a first direction, the yoke 833 travels in a proximaldirection (e.g., clamp arm pivots to closed configuration) and when thelead screw 893 rotates in a second direction, the yoke 833 travels in adistal direction (e.g., clamp arm pivots to open configuration). Thepulley assembly 892 can include a first pulley 895 and a second pulley896 with the first pulley 895 being coupled to the auxiliary shaft 890and the second pulley 896 being coupled to the lead screw 893 such thatrotation of the auxiliary shaft 890 causes the first pulley 895 torotate and transmit a torque to the second pulley 896 thereby causingthe lead screw 893 to rotate.

In some circumstances, manual control of the clamp arm can be desired,such as during loss of power and/or when the tool assembly isdisconnected from a robotic arm and the clamp arm needs to be moved intothe closed configuration in order to remove the end effector from thepatient and trocar. For example, the tool assembly 820 can include amanual controller (not shown), such as a lever, button, or latch, thatcan extend from the yoke 833 and through the housing 822 such that auser can manipulate the manual controller to move the yoke 833 betweenthe distal and proximal positions thereby manually controlling thepivoting the clamp arm between the open and closed configurations,respectively. Furthermore, the yoke can include a split nut (not shown)such that actuation of the manual controller can spread apart the splitnut thereby uncoupling the yoke 833 to the lead screw 893. To reset theyoke 833 and lead screw 893 coupling, such as in preparation to couplethe tool assembly to a robotic arm, the split nut can be reengaged. Asecondary process step may be necessary following such manual control inorder to allow the control unit to determine the position of the yoke833, such as relative to the lead screw 893. Such secondary process stepcan be performed, for example, after coupling the tool assembly to therobotic arm.

Any of the tool assemblies described herein can include various powerswitch mechanisms that control the delivery of power to the toolassemblies. Such power switch mechanisms can provide a safety feature toensure persons handling the tool assemblies do not get electrocuted. Forexample, a surgeon can perform a surgical procedure with the toolassembly and at some point hand the tool assembly to a nurse, such as toallow the nurse to clean a part of the tool assembly. The power switchmechanism can ensure that power is appropriately shut off within thetool assembly to ensure the nurse does not get electrocuted whilecleaning the tool assembly.

For example, in some embodiments, the power switch mechanisms can be incommunication with a generator, a foot switch, and a hand activationsuch that which ever one is activated first, that one gets priority andthe others are either turned off or ignored. In some embodiments, thepower switch mechanisms can include a manual control that a user canselect via a toggle between surgeon controls or bedside control. Forexample, the toggle can be on the generator. In some embodiments, thepower switch mechanisms can include a toggle on the tool assembly thatallows the bedside user to take control of the tool assembly. In someembodiments, the power switch mechanisms can include an activeselection, e.g., a menu, button or switch on a console, etc. In someembodiments, the power switch mechanisms can include automatic controlvia a docking switch on the tool assembly that knows when it is dockedto the robotic arm and when it is not. For example, when the toolassembly is mounted to the robotic arm, the user or surgeon can havecontrol. When the tool assembly is removed from the robotic arm, handactivation can become active and the user or surgeon can lose control ofthe tool assembly.

Preferably, components of the invention described herein will beprocessed before use. First, a new or used instrument is obtained and ifnecessary cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK bag. The container and instrumentare then placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high energy electrons.The radiation kills bacteria on the instrument and in the container. Thesterilized instrument can then be stored in the sterile container. Thesealed container keeps the instrument sterile until it is opened in themedical facility.

Typically, the device is sterilized. This can be done by any number ofways known to those skilled in the art including beta or gammaradiation, ethylene oxide, steam, and a liquid bath (e.g., cold soak).An exemplary embodiment of sterilizing a device including internalcircuitry is described in more detail in U.S. Pat. No. 8,114,345 filedFeb. 8, 2008 and entitled “System And Method Of Sterilizing AnImplantable Medical Device.” It is preferred that device, if implanted,is hermetically sealed. This can be done by any number of ways known tothose skilled in the art.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. A surgical tool, comprising: a housing; a shaftassembly extending through the housing and extending distally from thehousing, the shaft assembly having a distal end with a blade and a clamparm pivotally coupled to the blade; an actuation assembly including afirst actuator, and a second actuator, and a compound gear; and a yokehaving an elongated body that is disposed within the housing, the yokebeing operatively coupled between the clamp arm and the actuationassembly such that linear movement of the first actuator causeslongitudinal translation of the yoke in a first direction and linearmovement of the second actuator causes longitudinal translation of theyoke in a second direction that is opposite the first direction so as tomove the clamp arm between the open and closed positions; wherein thecompound gear operably couples the first and second actuators to theyoke, and wherein the compound gear includes a first gear and a secondgear that is coupled to the first gear such that the first gear and thesecond gear rotate together, the first gear having a first diameter andthe second gear having a second diameter that is less than the firstdiameter.
 2. The surgical tool of claim 1, further comprising anultrasonic transducer disposed within the housing and coupled to theblade for delivering ultrasonic energy to the blade.
 3. The surgicaltool of claim 1, wherein the housing is configured to couple to a driverof a robotic arm of a robotic surgical system.
 4. The surgical tool ofclaim 1, wherein the first actuator and the second actuator engageopposing sides of the first gear, and wherein the yoke engages thesecond gear.
 5. A surgical tool, comprising: a housing; a shaft assemblyextending through the housing and extending distally from the housing,the shaft assembly having a distal end with a blade and a clamp armpivotally coupled to the blade; an actuation assembly including a firstactuator and a second actuator; and a yoke having an elongated body thatis disposed within the housing, the yoke being operatively coupledbetween the clamp arm and the actuation assembly such that linearmovement of the first actuator causes longitudinal translation of theyoke in a first direction and linear movement of the second actuatorcauses longitudinal translation of the yoke in a second direction thatis opposite the first direction so as to move the clamp arm between theopen and closed positions; wherein at least one of the first actuatorand the second actuator comprises at least one protrusion formed on theyoke and extending through an opening in the housing.
 6. The surgicaltool of claim 5, further comprising an ultrasonic transducer disposedwithin the housing and coupled to the blade for delivering ultrasonicenergy to the blade.
 7. The surgical tool of claim 5, wherein the yokeis operatively coupled to at least one of the first actuator and thesecond actuator by a pulley assembly.
 8. The surgical tool of claim 5,wherein the yoke is operatively coupled to at least one of the firstactuator and the second actuator by a pinion gear.
 9. The surgical toolof claim 5, wherein the housing is configured to couple to a driver of arobotic arm of a robotic surgical system.
 10. The surgical tool of claim5, wherein the actuation assembly includes a compound gear that operablycouples the first and second actuators to the yoke.
 11. The surgicaltool of claim 10, wherein the compound gear includes a first gear and asecond gear that is coupled to the first gear such that the first gearand the second gear rotate together.
 12. The surgical tool of claim 11,wherein the first actuator and the second actuator engage opposing sidesof the first gear, and wherein the yoke engages the second gear.
 13. Thesurgical tool of claim 11, wherein the first gear has a first diameterand the second gear has a second diameter that is less than the firstdiameter.
 14. A surgical tool, comprising: a housing; a shaft assemblyextending through the housing and extending distally from the housing,the shaft assembly having a distal end with a blade and a clamp armpivotally coupled to the blade; an actuation assembly having a firstactuator, a second actuator, and a compound gear; and a single yokedisposed within the housing, the single yoke being operatively coupledbetween the clamp arm and the actuation assembly such that linearmovement of the first actuator and linear movement of the secondactuator cause longitudinal translation of the single yoke in a firstdirection and a second, opposite direction, respectively, along theshaft assembly to thereby move the clamp arm between the open and closedpositions; wherein the compound gear operably couples the first andsecond actuators to the yoke, and wherein the compound gear includes afirst gear and a second gear that is coupled to the first gear such thatthe first gear and the second gear rotate together, the first gearhaving a first diameter and the second gear having a second diameterthat is less than the first diameter.
 15. The surgical tool of claim 14,further comprising an ultrasonic transducer disposed within the housingand coupled to the blade for delivering ultrasonic energy to the blade.16. The surgical tool of claim 14, wherein at least one of the firstactuator and the second actuator comprises at least one protrusionformed on the yoke and extending through an opening in the housing. 17.The surgical tool of claim 14, wherein the housing is configured tocouple to a driver of a robotic arm of a robotic surgical system. 18.The surgical tool of claim 14, wherein the first actuator and the secondactuator engage opposing sides of the first gear, and wherein the yokeengages the second gear.